Thanks to all! @Ted:I have used my wacom, of course. but only to draw the shapes. Both with the bezier tool and the pen tool. The Outline is a 'normal' outline, set to 'behind fill'-mode. I am going to cover that later in a tutorial, I have still much pics like this one to upload...

Doh!! Sorry Ted, I've missed the real content of your question: for the linework INSIDE the shapes (to mimic folds and wrinkles) I used the artistic media tool. But I converted the strokes with my macro and cut them out of the main shape, to maintain the original outline properties of it. The shades of the main shapes were done with several fountain filled shapes.Drawn with a wacom.